science and truth

December 9, 2007

Philosophers of science have discovered that it is difficult, and may prove impossible, to provide an understanding of science that meets the following criteria:

1. It allows us to include all the theories currently embraced by the scientific community.
2. It allows to exclude the superstitions that mimic science, like astrology.
3. It tells a true story about how scientists do their work.

Ian Hacking sums up the situation in Representing and Intervening. Folks like Karl Popper and Rudolf Carnap worked on 1 and 2 diligently. Thomas Kuhn addressed 3 and sank their work beyond salvage. (If you are working on a philosophy of science, in particular, it is profoundly uncool to just build an elegant conceptual structure without any concern for how it matches up with the observable situation.) In 1981 Larry Laudan summed up the general conclusions one could draw from the history of science and the observation of how science is carried out currently.

1. Theory transitions are not cumulative. The new theory does not preserve all the logical or empirical content of the old theory.

2. Theories can be accepted in spite of anomalies, and rejected in spite of empirical confirmation.

3. The principles of scientific rationality which scientists use to evaluate theories are not permanently fixed, but have changed over time, i.e. they are specific and local.

4. The acceptance and rejection of theories play a minor role in scientific research. Scientists have to take a broad range of “cognitive stances” toward theories.

5. The co-existence of rival theories is the rule rather than the exception.

Also, Laudan wrote: Given the notorious difficulties with notions of 'approximate truth' – at both the semantic and epistemic levels – it is implausible that characterizations of scientific progress which view evolution towards greater truth-likeness as the central aim of science will allow one to represent science as a rational activity. This is hugely important. It seems obvious that rationality is about how we arrive at truth, and that science is the quintessential rational activity. In fact, these things cannot be made to fit together.

Not to overstate the case: there still are good reasons to consider certain theories true. A theory can be accurate, that is, by and large fit existing experimental data. It can be internally consistent. It can fit together with other accepted theories, It can be “broad in scope and rich in consequences,” as Hacking puts it. It can be simple in structure, and fruitful. However, those values or criteria are never sufficient to make the judgement call between competing theories. “Other qualities of judgement come into play,” Hacking writes, “qualities for which there could be, in principle, no algorithm…”

Hacking resolves the problem by rejecting the notion that it is particularly important: “…I think that reality has more to do with what we do in the world than with what we think about it.” (See Eliezer Yudowsky's “The Simple Truth.”) I have a lot of sympathy with that view. Life doesn't always have to be complicated. Hacking describes the experiment that converted him to realism. Nuclear physicists at Stanford took a ball of superconducting niobium and gradually altered its electrical charge, looking for a fractional electric charge called a quark. To increase the charge, they sprayed it with positrons, and to decrease the charge, they sprayed it with electrons. So far as I'm concerned, Hacking writes, if you can spray them then they are real. That's the naive view of truth. You can leave naive truth behind by doubting any of the many ideas that underlie that statement: we altered the charge by spraying it with electrons. You can ask, How do you know that's true? and when you get an answer, ask, How do you know that is true? Latour calls this “opening the black box.” We could simply call it skepticism. Hacking acknowledges he has no satisfactory answer for all the skeptics. The theory about electrons is doubtful, or “approximately true” (i.e. false). That doesn't mean electrons aren't real. You have to be willing to let life be simple sometimes. It's not always necessary to open the black box. Is what's most important really to understand the world, or is it not to change it?

So much philosophical and metaphysical thinking amounts to little more than useless speculations. The idea of reserving the term “reality” for those situations in which we participate, where we intervene and take action, has a lot of appeal.

The problem comes when the naive view of truth allows the idea of God to remain meaningful and helpful to people. There are more than a few folks who become metaphysicians on the spot to explain why this cannot be the case. As far as I've seen, however, there is no way to let out the skepticism without its attacking everything, including the foundations of any atheistic worldview. Why shouldn't this amount to a stalemate?